The present invention relates generally to a method of manufacturing a planarised reflective layer for micromirror devices. Micromirror devices require a substantially planarised reflective layer to minimize optical loss due to topography interference. Therefore, fabricating a substantially planarised reflective layer is absolutely crucial. However, the method of manufacturing the same according to conventional methods are complex as it requires various deposition, masking and etching steps. FIG. 1 is a cross-sectional view of a micromirror device comprising a reflective layer manufactured according to conventional methods. According to the conventional methods, an intermediary layer, normally amorphous-Silicon (104), is deposited and planarised prior to depositing an aluminium reflective layer (102). This results in a complex micromirror structure as well as a complex method of manufacturing the same.